PSA stands for Professional Sports Authenticator and they are the largest and most prestigious of the major sports card grading companies. Owned by Collectors, PSA was established in 1991 to bring the concept of grading to the sports card industry. Learn more about the history of PSA and Collectors here.
PSA offers many services including sports card authentication and grading, autograph authentication and grading, plus similar services for other collectible memorabilia.
Learn more about grading sports cards here.